Rails of a railroad system are typically supported on ties (made of wood, concrete, etc.) using plate assemblies. Each plate assembly normally may include, in sequence, a pad resting on a tie, a flat steel plate that has a sleeve-shaped shoulder resting on the pad, a clip and an insulator. The clip typically has two legs, is made of high-grade steel and acts as a spring forcing a foot or flange of the rail against the plate. This action ensures that the rail stays in position and does not move excessively as railroad cars pass over it.
For new installations, sections of track can be preassembled with the rails mounted on ties before the sections are laid. When tracks need repair or reconstruction, the various components discussed above must be assembled in the field. As part of this process, the clip is positioned manually with one of its legs extending partially into the shoulder. Once each pad assembly is positioned under the rail, the clip is pressed into position so that one of its legs passes through the sleeve and the other leg engages the rail. This step is performed either manually, with heavy hammers, or by using a pneumatic or hydraulic tool, which may be hand-held or vehicle-mounted. This whole process is called staging. An apparatus for performing staging is shown in U.S. Pat. No. 8,499,695.
A problem well-known in the field is that between the time the clip is positioned on the plate and the time that it is pressed into position to bias the rail against the plate, the clip is not restrained in any manner. Therefore, frequently the clip comes loose and separates from the plate. Once the clip moves out of place, it must be repositioned, thereby slowing down the staging. Moreover, any attempt made to press the clip into its final place when it is out of position may result in accidents and or damage to some of the other components of the plate assembly.
There have been attempts to resolve this problem in the past but by and large they were not successful.